Merge tag 'sound-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...

[cascardo/linux.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 97bc62c..84a7510 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -661,10 +661,10 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
 
        INIT_LIST_HEAD(&ctx->active_reqs);
 
-       if (percpu_ref_init(&ctx->users, free_ioctx_users))
+       if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
                goto err;
 
-       if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs))
+       if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
                goto err;
 
        ctx->cpu = alloc_percpu(struct kioctx_cpu);
@@ -793,6 +793,8 @@ void exit_aio(struct mm_struct *mm)
 
        for (i = 0; i < table->nr; ++i) {
                struct kioctx *ctx = table->table[i];
+               struct completion requests_done =
+                       COMPLETION_INITIALIZER_ONSTACK(requests_done);
 
                if (!ctx)
                        continue;
@@ -804,7 +806,10 @@ void exit_aio(struct mm_struct *mm)
                 * that it needs to unmap the area, just set it to 0.
                 */
                ctx->mmap_size = 0;
-               kill_ioctx(mm, ctx, NULL);
+               kill_ioctx(mm, ctx, &requests_done);
+
+               /* Wait until all IO for the context are done. */
+               wait_for_completion(&requests_done);
        }
 
        RCU_INIT_POINTER(mm->ioctx_table, NULL);
@@ -1111,6 +1116,12 @@ static long aio_read_events_ring(struct kioctx *ctx,
        tail = ring->tail;
        kunmap_atomic(ring);
 
+       /*
+        * Ensure that once we've read the current tail pointer, that
+        * we also see the events that were stored up to the tail.
+        */
+       smp_rmb();
+
        pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
 
        if (head == tail)